U.S. patent number 7,281,124 [Application Number 10/870,188] was granted by the patent office on 2007-10-09 for establishing a virtual drive accessible to pre-boot and operating system runtime phases.
This patent grant is currently assigned to Intel Corporation. Invention is credited to Michael A. Rothman, Vincent J. Zimmer.
United States Patent |
7,281,124 |
Rothman , et al. |
October 9, 2007 |
Establishing a virtual drive accessible to pre-boot and operating
system runtime phases
Abstract
A method, system and article of manufacture to establish a
virtual drive accessible to pre-boot and operating system runtime
phases. A virtual drive is constructed from a physical storage
device of a computer system during a pre-boot phase of the computer
system. A virtual drive controller is initialized during the
pre-boot phase to support the virtual drive. Information on the
virtual drive is accessed using the virtual drive controller by
firmware during the pre-boot phase. The information on the virtual
drive is accessed using the virtual drive controller by an
operating system (OS) of the computer system during an OS runtime
phase, wherein the information is comprehensible by the firmware
and the OS.
Inventors: |
Rothman; Michael A. (Puyallup,
WA), Zimmer; Vincent J. (Federal Way, WA) |
Assignee: |
Intel Corporation (Santa Clara,
CA)
|
Family
ID: |
35658617 |
Appl.
No.: |
10/870,188 |
Filed: |
June 17, 2004 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20060020779 A1 |
Jan 26, 2006 |
|
Current U.S.
Class: |
713/1; 713/100;
713/2; 718/1; 718/100; 718/101; 718/102; 718/103; 718/104; 718/105;
718/106; 718/107; 718/108 |
Current CPC
Class: |
G06F
9/4401 (20130101); G06F 9/45533 (20130101) |
Current International
Class: |
G06F
9/00 (20060101); G06F 15/177 (20060101); G06F
9/24 (20060101) |
Field of
Search: |
;713/1,2,100
;718/1-108 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Extensible Firmware Interface Specification, version 1.10, Dec. 1,
2002, http://developer.intel.com/technology/efi, Section 1
(1-1-1-14), Section 3 (3-1-3-8), Total pp. (including title page
& table of contents) 46. cited by other .
Intel.RTM. Platform Innovation Framework for EFI, Version 0.9, Sep.
16, 2003, www.intel.com/technology/framework, pp. 11-18, 61-66,
Total pages (including title page & table of contents) 21.
cited by other.
|
Primary Examiner: Perveen; Rehana
Assistant Examiner: Sugent; James F.
Attorney, Agent or Firm: Blakely, Sokoloff, Taylor &
Zafman LLP
Claims
What is claimed is:
1. A method, comprising: constructing a virtual drive from a
physical storage device of a computer system during a pre-boot
phase of the computer system, wherein constructing the virtual
drive includes: retrieving a logical block address (LBA) range
designated for the virtual drive; and assigning a portion of
logical block addresses of the physical storage device to the
virtual drive based on the LBA range; initializing a virtual drive
controller during the pre-boot phase, the virtual drive controller
to support the virtual drive; accessing information on the virtual
drive using the virtual drive controller by firmware of the
computer system during the pre-boot phase; and accessing the
information on the virtual drive using the virtual drive controller
by an operating system of the computer system during an operating
system runtime phase, wherein the information is comprehensible by
the firmware and the operating system and wherein the virtual drive
is perceived by the firmware and the operating system as a separate
drive from a device drive in the physical storage device.
2. The method of claim 1 wherein the LBA range is stored in
non-volatile storage of the computer system.
3. The method of claim 1 wherein accessing the information on the
virtual drive comprises: trapping an access request to the
information by the virtual drive controller, wherein the access
request includes a virtual drive logical block address; and
converting the virtual drive logical block address to a physical
storage device logical block address.
4. The method of claim 3, further comprising passing the access
request to an input/output controller associated with the physical
storage device, the access request including the converted virtual
drive logical block address.
5. The method of claim 1, further comprising accessing the
information on the virtual drive using the virtual drive controller
by the firmware during the operating system runtime phase.
6. The method of claim 1 wherein the information is in a Portable
Executable (PE) file format.
7. The method of claim 1 wherein the physical storage device
includes at least one of a hard disk, a flash memory device, or a
random access memory drive.
8. The method of claim 1 wherein the physical storage device
comprises a network storage device coupled to the computer system
through a network.
9. The method of claim 1, further comprising: launching a virtual
machine monitor (VMM), the VMM including the virtual drive
controller; and launching a virtual machine (VM) supported by the
VMM, the VM to support the firmware and the operating system.
10. The method of claim 1 wherein the firmware and the virtual
drive controller operate substantialiy in accordance with an
Extensible Firmware Interface (EFI) specffication.
11. The method of claim 1, further comprising enforcing a policy of
the virtual drive controller to prevent information not
comprehensible by the firmware and the operating system from being
stored on the virtual drive.
12. An article of manufacture comprising: a tangible
machine-accessible storage medium including a plurality of
instructions which when executed perform operations comprising:
constructing a virtual drive from a physical storage device of a
computer system during a pre-boot phase of the computer system,
wherein constructing the virtual drive includes: retrieving a
logical block address (LBA) range designated for the virtual drive;
and assigning a portion of logical block addresses of the physical
storage device to the virtual drive based on the LBA range;
initializing a virtual drive controller during the pre-boot phase,
the virtual drive controller to support the virtual drive;
accessing a file on the virtual drive using the virtual drive
controller by firmware of the computer system during the pre-boot
phase of the computer system; and accessing the file on the virtual
drive using the virtual drive controller in response to a request
from an operating system of the computer system during an operating
system runtime phase, wherein the file is in a file format
comprehensible by the firmware and the operating system and wherein
the virtual drive is perceived by the firmware and the operating
system as a separate drive from a device drive in the physical
storage device.
13. The article of manufacture of claim 12 wherein execution of the
plurality of instructions further perform operations comprising:
launching a virtual machine monitor (VMM), the VMM including the
virtual drive controller; and launching a virtual machine (VMM)
supported by the VMM, the VMM to support the finnware and the
operating system.
14. The article of manufacture of claim 12 wherein accessing the
file on the virtual drive comprises: trapping an access request to
the file by the virtual drive controller, wherein the access
request includes a virtual drive logical block address; converting
the virtual drive logical block address to a physical storage
device logical block address; and passing the access request to an
input/output controller associated with the physical storage
device, the access request including the converted virtual drive
logical block address.
15. The article of manufacture of claim 12 wherein the physical
storage device includes at least one of a hard disk, a flash memory
device, or a random access memory drive.
16. The article of manufacture of claim 12 wherein the physical
storage device comprises a network storage device coupled to the
computer system through a network.
17. The article of manufacture of claim 12 wherein the file format
includes a Portable Executable (PE) file format.
18. The article of manufacture of claim 12 wherein the firmware and
the virtual drive controller operate substantially in accordance
with an Extensible Firmware Interface (EFI) specffication.
19. A computer system, comprising: a processor; a hard disk drive
operatively coupled to the processor; and at least one non-volatile
storage device operatively coupled to the processor, the at least
one non-volatile storage device including firmware instructions
which when executed by the processor perform operations comprising:
constructing a virtual drive from the hard disk drive during a
pre-boot phase of the computer system, wherein constructing the
virtual drive includes: retrieving a logical block address (LBA)
range designated for the virtual drive; and assigning a portion of
logical block addresses of the hard disk drive to the virtual drive
based on the LBA range; initializing a virtual drive controller
during the pre-boot phase, the virtual drive controller to support
the virtual drive; accessing a file on the virtual drive using the
virtual drive controller by firmware of the computer system during
the pre-boot phase; and accessing the file on the virtual drive
using the virtual drive controller in response to a request from an
operating system of the computer system during an operating system
runtime phase, wherein the file is in a file format comprehensible
by the firmware and the operating system and wherein the virtual
drive is perceived by the firmware and the operating system as a
separate drive from a device drive in the physical storage
device.
20. The computer system of claim 19 wherein execution of the
plurality of firmware instructions further perform operations
comprising accessing the file on the virtual drive using the
virtual drive controller by the firmware during the operating
system runtime phase.
21. The computer system of claim 19 wherein accessing the file on
the virtual drive comprises: trapping an access request to the file
by the virtual drive controller, wherein the access request
includes a virtual drive logical block address; converting the
virtual drive logical block address to a hard disk drive logical
block address to generate a converted virtual drive logical block
address; and passing the access request to an input/output
controller associated with the hard disk drive, the access request
including the converted virtual drive logical block address.
22. The computer system of claim 19 wherein the firmware
instructions to operate substantially in compliance with an
Extensible Firmware Interface (EFI) specification.
Description
BACKGROUND
1. Field
Embodiments of the invention relate to the field of computer
systems and more specifically, but not exclusively, to establishing
a virtual drive accessible to pre-boot and operating system runtime
phases.
2. Background Information
Generally, the pre-boot phase is defined as the period of time
between computer system startup and the OS taking control of the
system. At the startup of a typical computer system, firmware is
loaded from non-volatile storage, such as Read-Only Memory (ROM),
and executed. The firmware is sometimes referred to as the system
Basic Input/Output System (BIOS). The firmware initializes the
platform hardware, performs system tests, and prepares the system
for the operating system (OS) to take control.
When the OS takes control of the system, the period commonly known
as OS runtime begins. During OS runtime, the firmware may act as an
interface between software and hardware components of a computer
system. Such interface services include assisting with software
interrupts.
In current systems, information cannot be shared between the
pre-boot phase and the OS runtime phase of the platform. There is
no storage resource that is commonly accessible to the pre-boot and
the OS runtime environments. Thus, file sharing between the phases
is problematic. Also, most operating systems store information
based on a proprietary file system and file format that cannot be
comprehended by the firmware of the computer system.
BRIEF DESCRIPTION OF THE DRAWINGS
Non-limiting and non-exhaustive embodiments of the present
invention are described with reference to the following figures,
wherein like reference numerals refer to like parts throughout the
various views unless otherwise specified.
FIG. 1 is a block diagram illustrating one embodiment of an
environment that supports a virtual drive in accordance with the
teachings of the present invention.
FIG. 2 is a block diagram illustrating one embodiment of an
environment that supports a virtual drive in accordance with the
teachings of the present invention.
FIG. 3 is a block diagram illustrating one embodiment of a virtual
drive in accordance with the teachings of the present
invention.
FIG. 4 is a block diagram illustrating one embodiment of an
environment that supports a virtual drive in accordance with the
teachings of the present invention.
FIG. 5A is a flowchart illustrating one embodiment of the logic and
operations to establish a virtual drive accessible to pre-boot and
OS runtime phases in accordance with the teachings of the present
invention.
FIG. 5B is a flowchart illustrating one embodiment of the logic and
operations to access a virtual drive during pre-boot and OS runtime
phases in accordance with the teachings of the present
invention.
FIG. 6 is a block diagram illustrating one embodiment of an
exemplary computer system to implement embodiments of the present
invention.
DETAILED DESCRIPTION
In the following description, numerous specific details are set
forth to provide a thorough understanding of embodiments of the
invention. One skilled in the relevant art will recognize, however,
that embodiments of the invention can be practiced without one or
more of the specific details, or with other methods, components,
materials, etc. In other instances, well-known structures,
materials, or operations are not shown or described in detail to
avoid obscuring understanding of this description.
Reference throughout this specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the present invention. Thus,
the appearances of the phrases "in one embodiment" or "in an
embodiment" in various places throughout this specification are not
necessarily all referring to the same embodiment. Furthermore, the
particular features, structures, or characteristics may be combined
in any suitable manner in one or more embodiments.
Referring to FIG. 1, one embodiment of a computer system 100 is
shown. Computer system 100 includes a Virtual Machine (VM) 102
layered on top of a Virtual Machine Monitor (VMM) 104. VMM 104 is
layered on top of the platform hardware 106. While FIG. 1 shows one
VM 102, computer system 100 may include multiple VMs layered on VMM
104.
A VM behaves like a complete physical machine. Usually, each VM
session is given the illusion by the VMM that it is the only
physical machine. The VMM usually takes control whenever a VM
attempts to perform an operation that may affect the whole computer
system. Each VM supports a corresponding OS and firmware. Multiple
VM sessions are separate entities and usually isolated from each
other by the VMM. If one VM crashes or otherwise becomes unstable,
the other VM should not be adversely affected.
VM 102 includes an operating system (OS) 108 and firmware 112. OS
108 includes at least one application 110 and device drivers 111.
During the pre-boot phase, firmware 112 is loaded from non-violate
storage. Generally, firmware 112 initializes the system hardware
and then loads and initiates the OS loader. The OS runtime phase
begins when the OS takes control of the system.
Firmware 112 may also provide services to OS 108 during OS runtime.
In one embodiment, such services include supporting interaction
with hardware 106 and handling software interrupts. In the
embodiment of FIG. 1, OS 108 may communicate directly with VMM 104
to access platform hardware 106. The OS 108 may also request
services from firmware 112 and the firmware 112 subsequently
interacts with the hardware 106 via VMM 104. Additionally, the
firmware 112 may initiate a transaction with hardware 106 without
prompting from OS 108. In one embodiment, OS 108 and firmware 112
are unaware of that their interaction with platform hardware 106 is
managed by VMM 104. OS 108 and firmware 112 are clients of VMM 104
to be serviced and monitored by the VMM 104.
Embodiments of firmware 112 may employ a firmware environment known
as the Extensible Firmware Interface (EFI) (Extensible Firmware
Interface Specification, Version 1.10, Dec. 1, 2002, available at
http://developer.intel.com/technology/efi.) EFI enables firmware,
in the form of firmware modules and drivers, to be loaded from a
variety of different resources, including flash memory devices,
option ROMs (Read-Only Memory), various persistent storage devices
(e.g., hard disks, CD-ROM (Compact Disk-Read Only Memory), etc.),
or from one or more computer systems over a computer network. One
embodiment of an implementation of the EFI specification is
described in the Intel.RTM. Platform Innovation Framework for EFI
Architecture Specification--Draft for Review, Version 0.9, Sep. 16,
2003 (available at www.intel.com/technology/framework), hereinafter
referred to as the "Framework." It will be understood that
embodiments of the present invention are not limited to the
"Framework" or implementations in compliance with the EFI
specification.
In an EFI compliant system, EFI provides Boot Services are
available during the pre-boot phase while Runtime Services are
available during the pre-boot phase and OS runtime phase. In the
"Framework" implementation of EFI, Boot Services include, but are
not limited to, Memory Services to allocate memory, Image Services
to load and execute executable image files, and Driver Support
Services to access pre-boot drivers. Runtime Services in the
"Framework" include, but are not limited to, Variable Services to
access environmental variables from non-volatile storage and Status
Code Services to send status codes to a system log.
Under the "Framework", when an OS loader is ready to assume control
of the platform and all platform resource management, an
ExitBootServices() call is issued. Once the ExitBootServices()
returns successfully, Boot Services are no longer available, but
Runtime Services survive into OS runtime. Under the "Framework,"
when the call to ExitBootServices() returns, OS runtime has been
entered.
Referring again to FIG. 1, VMM 104 includes a virtual drive
controller 114 to support a virtual drive 116. In one embodiment,
virtual drive controller 114 is loaded from non-volatile storage,
such as a flash memory device. In one embodiment, VMM 104 supports
virtual drive controller 114.
Platform hardware 106 includes virtual drive 116 and non-volatile
storage 118. Non-volatile (NV) storage 118 includes a magnetic
storage device, an optical storage device, a non-violate storage
device, such as flash memory, or the like. In the embodiment of
FIG. 1, NV storage 118 has stored a virtual drive logical base
address (LBA) range 120 used in constructing virtual drive 116
(discussed further below).
Virtual drive 116 is carved out of a physical storage device 126,
such that virtual drive 116 and device drive 122 are advertised to
VM 102 (and thus OS 108 and firmware 112). Platform hardware 106
also includes an input/output (I/O) controller 124 to support
access to physical storage device 126. In one embodiment, I/O
controller 124 includes an Integrated Drive Electronics (IDE)
controller, and physical storage device 126 includes an IDE
drive.
In one embodiment, firmware 112 and OS 108 may conduct transactions
with virtual drive 116 as if virtual drive 116 is a separate IDE
drive. IDE is a well-known standard for connecting storage devices
to a bus of a computer system (see, American National Standards
Institute (ANSI) Advanced Technology Attachment (ATA)
specifications). A follow-on version of IDE is called Enhanced
Integrated Drive Electronics (EIDE). It will be noted that the term
IDE is used herein to refer to all variants of the IDE/ATA
interface, including EIDE.
Usually, an IDE ribbon connects the motherboard to storage devices,
such as hard disk drives. When access to the storage device is
requested, a signal is sent to the IDE controller, which is usually
a chipset residing on the motherboard. The IDE controller uses the
IDE ribbon connectors to conduct the requested transaction with the
storage device. While most storage devices today have on-board
controllers, the IDE controller acts as an intermediary between the
storage device's controller and the rest of the computer
system.
In embodiments of the present invention, instead of allowing the
input/output traffic to go directly to I/O controller 124, the
virtual drive controller 114 may trap access to the I/O controller
124. The virtual drive controller 114 may re-route input/output
flow and re-represent certain query-type of commands regarding the
devices which the I/O controller 124 would normally represent.
Virtual drive controller 114 interacts with I/O controller 124 to
complete I/O requests. In one embodiment, from the point of view of
OS 108 and firmware 112, the virtual drive controller 114 is
indistinguishable from I/O controller 124.
In one embodiment, the virtual drive 116 may use a file system
comprehensible by both the firmware 112 and the OS 108. Such file
systems include, but are not limited to, File Allocation Table 12
(FAT12), FAT16, FAT32, or the like.
In another embodiment, information is maintained on the virtual
drive 116 in a file format that is comprehensible to both firmware
112 and the OS 108. One embodiment of such a file format includes
the Portable Executable (PE) file format, which is well known in
the art. The Microsoft Corporation introduced the PE file format
with Windows NT.RTM.. The PE file format serves as the executable
file format for Windows.RTM. operating systems. In an
implementation of EFI, Portable Executable and Common Object File
Format (PE/COFF) executable images are used (see, PE/COFF
Specification, Version 6.0, February 1999, available at
http://www.microsoft.com/whdc/hwdev/hardware/pecoff.mspx).
EFI may use a form of the PE file format for EFI images. EFI images
are a class of files defined by EFI that contain executable code.
Generally, there are three types of EFI images that can be loaded
and executed by EFI-compliant firmware. These are EFI Applications,
EFI OS Loaders, and EFI Drivers. In one embodiment, EFI
Applications include utilities and diagnostic tools that may be
used by firmware 112 and OS 108.
In one embodiment of the present invention, virtual drive
controller 114 may enforce policy as to the use of virtual drive
116. For example, the policy may designate that only PE files are
to be stored on virtual drive 116. Thus, if a user attempts to
store non-PE files on virtual drive 116, such as a Microsoft.RTM.
Word document, virtual drive controller 114 may block the
transaction and initiate an error message to the user.
Referring to FIG. 2, a computer system life cycle 200 is shown. At
startup, the computer system enters a pre-boot phase 202. During
pre-boot, virtual drive 116 is constructed and virtual drive
controller 114 is initialized to support virtual drive 116.
Firmware 112 may interact with virtual drive 116 using virtual
drive controller 114 during pre-boot phase 202.
Moving to the right along the life cycle 200, the computer system
enters OS runtime 204. During this phase, operating system 108 has
been loaded and is executing. OS 108 may conduct transactions with
virtual drive 116 via virtual drive controller 114 without going
through firmware 112. In other instances, OS 108 may request
services from firmware 112 for interaction with virtual drive 116.
Firmware 112 may also interact with virtual drive 116 during OS
runtime 204 without initiation from OS 108.
Turning to FIG. 3, an embodiment of constructing a virtual drive is
illustrated. In the embodiment of FIG. 3, a physical storage device
302 is shown as a hard disk drive. In other embodiments, physical
storage device 302 includes, but is not limited, to an optical disk
drive, a RAM (Random Access Memory) drive, a flash memory device,
or the like.
EIDE introduced logical block addressing into the IDE interface
family. Instead of referring to a cylinder, head, and sector number
of a disk, logical block addressing assigns a unique logical
address to each sector of the disk. Logical block addressing was
designed to allow addressing hard disks larger than 528 Megabytes
(MB). Disk sectors are numbered consecutively from zero to N-1,
wherein N is the number of disk sectors, without regard to the disk
geometry. While logical block addressing has originally designed
for hard disk drives, the logical block addressing scheme may be
applied to other storage devices, such as a flash memory devices,
Random Access Memory (RAM) drives, or the like.
Physical storage device logic block addresses 304 of physical
storage device 302 are shown in FIG. 3. LBAs 308 have been
designated for virtual drive 312, while LBAs 306 correspond to
device drive 310. It will be understood that the physical sectors
of physical storage device 302 assigned to virtual drive 312 may be
contiguous, sparse, or any combination thereof.
In the embodiment of FIG. 3, virtual drive LBAs 308 have been
renumbered from 0-299, but correspond to physical storage device
LBAs 700-999 of physical storage device 302. Device drive 310 has
been assigned LBAs 0-699 of physical storage device 302. As
discussed further below, when the firmware or OS requests to access
an LBA of the virtual drive, the virtual drive controller maps the
request to a corresponding LBA on the physical storage device
302.
Virtual drive 312 is perceived by the firmware and the OS as
another drive available to the computer system. The firmware and
the OS may not know that virtual drive 312 has been carved out of
another storage device on the computer system. In actuality, the
virtual drive controller proxies the I/O controller to handle I/O
requests to the virtual drive. The virtual drive controller passes
transactions to the I/O controller to execute the transactions to
the requested region of the physical storage device 302. For
example, the firmware and the OS may see device drive 310 as drive
(C:) and virtual drive 312 as drive (P:). In the embodiment of FIG.
3, virtual drive 312 has stored PE files 320 and 322 using a FAT32
file system 324.
In one embodiment, the LBA range stored for the virtual drive may
be defined by the following structures:
TABLE-US-00001 typedef struct { UINT64 LBANumber; /* starting point
of entry */ UINT32 SectorCount; /* number of sectors in this entry
*/ } LBA_ENTRY; typedef struct { UINT64 LBAEntryCount; /* total
number of entries */ //LBA_ENTRY LBAArray[ ]; array of entries }
LBA_DESCRIPTOR;
In one embodiment, numerous LBA entry points making up a sparse
arrangement may describe the virtual drive. In another embodiment,
the virtual drive may be described by a single LBA entry for one
unbroken LBA range.
Turning to FIG. 4, an embodiment of a virtual drive 412 is shown.
Computer system 100 is coupled to physical network storage 408 via
network 404. Virtual drive 412 is constructed from physical network
storage 408 according to embodiments described herein. The firmware
and OS of computer system 100 "see" network storage drive 410 and
virtual drive 412. In one embodiment, the stored LBA range used in
constructing virtual drive 412 may include the Internet Protocol
(IP) address of physical network storage 408.
In another embodiment, a remote file may be mounted as a virtual
drive 412. In this way, the remote file is available to the
computer system through all phases of the computer system. This
remote file is viewed as a drive by computer system 100.
In one embodiment, virtual drive 412 may include data shared by a
plurality of computer systems communicatively coupled to physical
network storage 408 via network 404. For example, physical network
storage 408 may be part of a network server to support client
systems of the network. In this particular embodiment, the virtual
drive 412 may include configuration applications that execute
during pre-boot of a client to send client configuration
information to the server. In another embodiment, virtual drive 412
may include diagnostics and/or utilities that are to be executed by
a client as described by a boot script on the client.
FIG. 5A shows a flowchart 500 illustrating one embodiment of the
logic and operations to establish a virtual drive. Beginning in a
block 504, a computer system is started/reset. Boot instructions
stored in the computer system firmware are loaded. In one
embodiment, the system boot instructions may begin initializing the
platform by conducting a Power-On Self-Test (POST) routine.
Proceeding to a block 506, a VMM and VM are launched. The VM is
supported by the VMM. In one embodiment, the VMM and VM operate
substantially in compliance with the EFI specification.
In a block 508, the LBA range for the virtual drive is retrieved.
In one embodiment, the LBA range is stored on the computer system
in a non-volatile storage device. In another embodiment, the LBA
range is retrieved from a storage device through a network
connection. In yet another embodiment, a user enters the LBA range
during the pre-boot phase.
Continuing to a block 510, the virtual drive is constructed based
on the retrieved LBA range. In a block 512, a virtual drive
controller is initialized to support the virtual drive. In one
embodiment, the virtual drive controller is initialized based on
the LBA configuration of the newly constructed virtual drive. In
another embodiment, the virtual drive controller is loaded from a
non-volatile storage device, such as flash memory. In yet another
embodiment, the virtual drive controller operates substantially in
compliance with the EFI specification.
Proceeding to decision block 514, the logic determines if the
firmware of the computer system has requested access to the virtual
drive. If the answer is yes, then the logic proceeds to a block 516
where the transaction with the virtual drive is conducted using the
virtual drive controller. Access to the virtual drive includes a
request to read or to write information to the virtual drive. In
one embodiment, the information is formatted such that it is
comprehensible by the firmware and the OS. After the transaction is
completed, the logic proceeds back to decision block 514.
Turning to FIG. 5B, an embodiment of the logic and operations to
conduct a transaction with the virtual drive is illustrated by
flowchart 550. In one embodiment, transactions with the virtual
drive are conducted by the firmware as if the virtual drive was an
IDE drive having an associated IDE controller. Embodiments of
transactions with the virtual drive by the OS may be conducted
similarly as described in flowchart 550.
Starting in a block 552, the firmware requests access to the
virtual drive. For example, the firmware may request to read LBA 1
of the virtual drive. In a block 554, the virtual drive controller
traps the access request to the virtual drive. Continuing to a
block 556, the virtual drive controller evaluates the access
request. In one embodiment, the virtual drive controller evaluates
the access request to determine if the request violates a policy of
the virtual drive controller. In another embodiment, the virtual
drive controller evaluates the access request to determine if it
was made to a valid virtual drive LBA.
Continuing to a block 558, the virtual drive controller converts
virtual drive LBA of the access request to a corresponding physical
drive LBA. Thus, continuing the example of a request to LBA 1, if
LBA 1 of the virtual drive corresponds to LBA 100 of the actual
physical drive, the virtual drive controller converts the
destination of the request accordingly. In one embodiment, the
virtual drive LBA may not need to be converted because it maps
directly to a corresponding physical storage device LBA. Proceeding
to a block 560, the virtual drive controller passes the access
request to the I/O controller associated with the physical storage
device for processing. The access request passed to the I/O
controller may include the converted virtual drive LBA.
Returning to FIG. 5A, if the answer to decision block 514 is no,
then the logic proceeds to a block 518 to boot the OS in the VM. As
discussed above, OS runtime begins when the OS takes control of the
system. In one embodiment, OS runtime starts with the OS loader
begins executing.
Continuing to a decision block 520, the logic determines if the OS
has requested access to the virtual drive. If the answer is yes,
then the logic proceeds to a block 522 to conduct the transaction
using the virtual drive controller. In one embodiment, the
transaction in block 522 is conducted similarly to the embodiment
of FIG. 5B. The logic then returns back to decision block 520.
If the answer to decision block 520 is no, then the logic continues
to decision block 524 to determine if the firmware has requested
access to the virtual drive. If the answer is yes, then the logic
proceeds to block 522 discussed above. If the answer is no, then
the logic returns to decision block 520.
Embodiments described herein provide a common repository that is
available during the pre-boot and OS runtime phases of a computer
system. This common repository allows information to be passed
between pre-boot and OS runtime environments. For example, a
firmware patch may be downloaded to the virtual drive during OS
runtime. The firmware patch is in a format common to the OS and the
firmware, such as the PE file format. On the subsequent pre-boot
phase of the computer system, the firmware may look to the virtual
drive for any executable files to be run. In this example, the
firmware may find the firmware patch on the virtual drive and
execute the file.
In another example, the virtual drive may provide fault tolerance
during a firmware update. A user may download a firmware update
during OS runtime and store the firmware update on the virtual
drive. Assume that during a firmware update procedure initiated
from OS runtime, a system failure occurs. Normally, on re-boot,
this may cause a system error because the firmware may be
corrupted.
However, according to embodiments described herein, the firmware
may find the firmware update on the virtual drive and execute the
update in the pre-boot phase. The firmware is capable of executing
the firmware update during pre-boot because the update is in a
format comprehensible by both the firmware and the OS. Thus, even
though a system error occurred during execution of the firmware
update at OS runtime, the update may still occur in the next
subsequent pre-boot phase.
FIG. 6 is an illustration of one embodiment of an example computer
system 600 on which embodiments of the present invention may be
implemented. Computer system 600 includes a processor 602 coupled
to a bus 606. Memory 604, storage 612, non-volatile storage 605,
and network interface 614 are also coupled to bus 606. Input/output
(I/O) device 618 is coupled to bus 606 via I/O controller 617.
Embodiments of computer system 600 include, but are not limited to
a desktop computer, a notebook computer, a server, a personal
digital assistant, a network workstation, or the like.
The computer system 600 may interface to external systems through
the network interface 614. Network interface 614 may include, but
is not limited to, a modem, a network interface card (NIC), or
other interfaces for coupling a computer system to other computer
systems. A carrier wave signal 623 is received/transmitted by
network interface 614. In the embodiment illustrated in FIG. 6,
carrier wave signal 623 is used to interface computer system 600
with a network 624, such as a local area network (LAN), a wide area
network (WAN), the Internet, or any combination thereof. In one
embodiment, network 624 is further coupled to a remote computer 625
such that computer system 600 and remote computer 625 may
communicate over network 624.
Processor 602 may include, but is not limited to, an Intel
Corporation x86, Pentium.RTM., Xeon.RTM., or Itanium.RTM. family
processor, a Motorola family processor, or the like. In one
embodiment, computer system 600 may include multiple processors.
Memory 604 may include, but is not limited to, Dynamic Random
Access Memory (DRAM), Static Random Access Memory (SRAM),
Synchronized Dynamic Random Access Memory (SDRAM), Rambus Dynamic
Random Access Memory (RDRAM), or the like. I/O device 618 may
include a keyboard, a mouse, a display, a printer, a scanner, or
the like.
The computer system 600 also includes non-volatile storage 605 on
which firmware and/or data may be stored. Non-volatile storage
devices include, but are not limited to, Read-Only Memory (ROM),
Flash memory, Erasable Programmable Read Only Memory (EPROM),
Electronically Erasable Programmable Read Only Memory (EEPROM),
Non-Volatile Random Access Memory (NVRAM), or the like. Storage 612
includes, but is not limited to, a magnetic hard disk, a magnetic
tape, an optical disk, or the like. It is appreciated that
instructions executable by processor 602 may reside in storage 612,
memory 604, non-volatile storage 605, or may be transmitted or
received via network interface 614.
For the purposes of the specification, a machine-accessible medium
includes any mechanism that provides (i.e., stores and/or
transmits) information in a form readable or accessible by a
machine (e.g., a computer, network device, personal digital
assistant, manufacturing tool, any device with a set of one or more
processors, etc.). For example, a machine-accessible medium
includes, but is not limited to, recordable/non-recordable media
(e.g., read only memory (ROM), random access memory (RAM), magnetic
disk storage media, optical storage media, a flash memory device,
etc.). In addition, a machine-accessible medium may include
propagated signals such as electrical, optical, acoustical or other
form of propagated signals (e.g., carrier waves, infrared signals,
digital signals, etc.).
It will be appreciated that in one embodiment, computer system 600
may execute operating system software. For example, one embodiment
of the present invention utilizes Microsoft Windows.RTM. as the
operating system for computer system 600. Other operating systems
that may also be used with computer system 600 include, but are not
limited to, the Apple Macintosh operating system, the Linux
operating system, the Unix operating system, or the like. In one
embodiment, computer system 600 employs the Intel.RTM. Vanderpool
Technology (VT). VT facilitates the separation of VMs and the
transitions between VMs and the VMM.
The above description of illustrated embodiments of the invention,
including what is described in the Abstract, is not intended to be
exhaustive or to limit the embodiments to the precise forms
disclosed. While specific embodiments of, and examples for, the
invention are described herein for illustrative purposes, various
equivalent modifications are possible, as those skilled in the
relevant art will recognize. These modifications can be made to
embodiments of the invention in light of the above detailed
description.
The terms used in the following claims should not be construed to
limit the invention to the specific embodiments disclosed in the
specification. Rather, the following claims are to be construed in
accordance with established doctrines of claim interpretation.
* * * * *
References